The primary goal of the project is to further characterize those factors influencing in vitro insulin and glucagon secretion from the pancreas of normal and diabetic animals. Studies will include: 1. Role of calcium metabolism measured as Ca45 uptake and efflux on phasic insulin release from isolated islets. Studies will concentrate on the nature of the calcium--calcium exchange compartment and how it is influenced by secretagogue and metabolic inhibitors. 2. Role Zn65 insulin complex formation and dissociation on insulin storage and secretion. 3. Further characterization of interrelationship of K ion, sulfonylureas and insulin secretion on glucagon release. 4. Further characterization of the nature of impaired glucagon and insulin secretion from the perfused pancreas of the diabetic Chinese Hamster.